I haven’t dived PR yet; however every Oct. we do the Virgin Islands. Oct. is a great time to go. It is in hurricane season; however, in 20+ years we have had 1 hurricane (Omar in 2008). It is much less crowded and depending on which of the islands you go to some of the shops and restaurants are shut down or have restricted hours.
I’ll be honest with you my least favorite island to stay on is St. Thomas, it’s to crowded and very touristy. even during the slow season. It does have great shopping and it’s location gives the ability to explore both there and by way of the ferry both the BVI’’s and St John.
Good luck with the trip,
Scott